Hasil untuk "Electric apparatus and materials. Electric circuits. Electric networks"

Chuanzhi Tang, Jinlai Zhang, Yuanhao Yang et al.

Tajmon T. Vadukoote, Nathaniel Craft, Alyssa‐Jennifer Avestro et al.

ABSTRACT Supramolecular eutectogels based on 1,3:2,4‐dibenzylidenesorbitol (DBS) derivatives as low‐molecular‐weight gelators (LMWGs) are 3D‐printed via wet‐spinning. Solubility and assembly kinetics play key roles in LMWG printability in a deep eutectic solvent (DES), a process facilitated by the addition of water. On drying, the printed gels lose some water content, reaching a stable composition for optimal, reproducible electronic properties. The printed supramolecular eutectogels have high conductivities of ca. 5.0 mS/cm, enabling them to be used as soft conductive wires in simple electronic circuits. Furthermore, depending on LMWG structure, they can be selectively reacted with Au(III) and loaded with gold nanoparticles, demonstrating the tunability of this supramolecular approach at the molecular scale. The ability to print functional conductive gels with curved and flexible structures indicates the potential of LMWG eutectogels in the fabrication of soft electronic circuitry with future applications in bionanoelectronics.

David H. Gultekin, J. Thomas Vaughan, Devashish Shrivastava

We describe the relationship between the RF-induced temperature change in a conductive metallic implant during the MRI, B_1+rms, and RF power for RF pulse sequences, RF coils, and Tx/Rx combinations. We show that both temperature and RF power change with RF pulse sequences, RF coils, and Tx/Rx combinations, whereas B_1+rms changes only with RF pulse sequences but not RF coils and Tx/Rx combinations. As a result, induced heating is associated with RF power propagation and loss corresponding to the B_1+rms.

Xuanguang Zhang, Kaiqi Li, Jian Zhou et al.

Abstract The ovonic threshold switching (OTS) effect, observed in chalcogenide glasses (CGs), involves a reversible transition from a high‐resistive state (OFF state) to a conductive state (ON state) under an electric field. However, direct observation of the dynamic process of the OTS effect is challenging, leading to debate about the mechanism of the OTS effect. In this work, the OTS effect in GeSe2 glass is studied using ab initio molecular dynamics (AIMD) with electric fields. Before applying an electric field, the glass is in the OFF state. After applying electric fields of different strength, mid‐gap states appear and band tail states get wider. Atomic chains composed of Se atoms and a small number of Ge atoms, which contribute to some mid‐gap states, are formed by reversal of Peierls‐like distortion. These atomic chains result in chain‐like molecular orbitals. The percolation of the metastable channel through a reversal of the Peierls‐like distortion process on the atomic chains can be considered the cause of the transition to the ON state in GeSe2 glass. Upon removing the electric field, the glass returns to the OFF state. This study provides insight into the conduction mechanism of CGs.

Boualem Djezzar

The sixties (60s) and seventies (70s) of the last century have seen the takeoff of microelectronics. Since that, several countries, including Algeria, have adopted planned strategic programs to develop their domestic electronics. In this paper, we provide a historical review of the evolution of the electrical test benches developed at the Division of Microelectronics and Nanotechnology (DMN) of the “Centre de Développement des Technologies Avancées” (CDTA) or Center for Development of the Advanced Technologies. Starting from mid- nineties to up today, the electrical characterization platform has known different generations of test benches; from a simple setup to extract current-voltage (I-V) and capacitance-voltage (C-V) characteristics of semiconductor devices to more sophisticated ones to extract spectra of electrically detected magnetic resonance (EDMR). In addition, some benches have been developed to study reliability issue in metal oxide semiconductor (MOS) devices and integrated circuits (ICs), such as ionizing radiation effects, Fowler-Nordheim (FN) stress, hot-carrier injection (HCI), time-dependent dielectric breakdown (TDDB), and bias temperature instability (BTI). The obtained results have been published in well-known journals of the Institute of Electrical and Electronics Engineers (IEEE), the American Institute of Physics (AIP), and the Elsevier publishers.

Luciano F.S. Alves, Pierre Lefranc, Jean-Christophe Crebier et al.

This paper analyzes a novel packaging technique to improve the voltage-sharing performances of series-connected SiC-MOSFETs. The proposed method takes advantage of the parasitic capacitance network introduced by the packaging dielectric isolation layers to reduce the voltage imbalance across the series-connected devices. Firstly, the study carried out in this work explains how the parasitic capacitance networks introduced by the classic planar packaging and the gate drive circuits cause voltage imbalances across the devices. Therefore, a new packaging concept is analyzed to compensate for the effects of the gate driver parasitic capacitances. The concept is introduced and analyzed using equivalent models and mathematical approaches. To verify the analysis, the voltage sharing between two series-connected 1.2 kV SiC-MOSFETs is tested in a pulse test setup. The experimental results confirm that the proposed voltage-balancing technique can drastically improve the voltage-sharing performance of series-connected devices.

Wangying Xu, Jierui Lin, Yanwei Li et al.

Abstract There is a growing interest in exploring nanometer‐thin 2D oxide semiconductor transistors for future scaled and multifunctional (e.g., ultraflexible and high transparency) devices. However, further development is hindered due to the degraded device performance with nanometer‐thin 2D oxide semiconductor channels and the use of costly vacuum‐based techniques. Here, 2D (2.7 nm thick) c‐axis‐aligned crystalline In─S─O channel material processed from aqueous solution is reported. The 2D In─S─O transistors based on Si/SiO2 substrates exhibit high mobility (µ) of 22.15 cm2 V−1 s−1, on/off current ratio (Ion/Ioff) of ≈107, and good bias stress stability. Detailed investigations show that this achievement is attributed to the highly c‐axis‐aligned crystalline structure, well‐designed In─S─O channel material, and atomically smooth surface. Furthermore, the 2D In─S─O channel is integrated with an aqueous sol‐gel‐derived 6 nm thick high‐k ZrO2 insulator. The all‐aqueous‐solution‐based quasi‐2D In─S─O/ZrO2 devices show high µ of 15.65 cm2 V─1 s─1, Ion/Ioff of ≈106, and low operating voltage of 1.5 V. This 2D c‐axis‐aligned crystalline wide‐bandgap oxide semiconductor channel material opens tremendous opportunities for multifunctional, ultra‐scaled and low‐cost electronics.

Yue Gao, Wentao Jiang, Da Zeng et al.

This paper presents a systematic review of biomedical Ti alloys fabricated through additive manufacturing. It begins with an overview of the development of Ti metals and their applications in biomedical fields, particularly in orthopedic and dental implants. The review highlights recent advancements, such as the incorporation of porous structures. Key aspects of additive manufacturing for biomedical Ti alloys are explored, including material characteristics, preparation parameters, solidification behavior, and post-heat treatments, with emphasis on their effects on microstructure and material properties. This paper further summaries the current states of biomedical standards for Ti alloys, and concludes with a discussion of future trends, opportunities, and challenges in the additive manufacturing of biomedical Ti alloys, including advancements in material innovation, process optimization, and the integration of personalized implants. This review aims to provide valuable insights into the ongoing developments and future directions for additive manufacturing biomedical Ti alloys.

Aijaz H. Lone, Meng Tang, Daniel N. Rahimi et al.

Abstract Spintronic devices based on DWss and skyrmions have shown significant potential for applications in energy‐efficient data storage and beyond CMOS computing architectures. Based on the ferromagnetic multilayer spintronic devices, a magnetic field‐gated and current‐controlled spintronic Leaky Integrate‐and‐Fire (LIF) neuron with memtransistor properties is showcased. The memtransistor property allows for tuning firing characteristics through external magnetic fields and current pulses. A LIF neuron model is developed based on measured characteristics to integrate the device into system‐level Spiking Neural Networks (SNNs). The scalability of the neuron device is confirmed with the micromagnetic simulations in a domain‐wall magnetic tunnel junction device. When integrated into SNN and convolutional SNN frameworks, the device achieves classification precision above 96%. The study highlights the device's potential as a neuron in hardware SNN architecture‐based neuromorphic computing applications, combining memtransistor properties of the device and high pattern classification accuracy. The results demonstrate a promising path toward developing energy‐efficient and scalable neural networks.

Haesung Jung, Quang Dang Truong, Hanho Lee

The advent of quantum computers, with their immense computational potential, poses significant threats to traditional cryptographic systems. In response, NIST announced the quantum-resistant Module Lattice-based Key Encapsulation Mechanism (ML-KEM) standard in 2024. This paper presents an efficient hardware architecture for the ML-KEM scheme, capable of supporting all algorithms and flexibly adapting to different security levels. The proposed design achieves a balance between high performance and low hardware resource consumption, making it suitable for deployment across various FPGA platforms. Key innovations include the Unified Polynomial Arithmetic Module (UniPAM), capable of handling all polynomial arithmetic operations, and an optimized hash module for the SHA-3 variants integral to ML-KEM. Additionally, the design introduces an efficient timing diagram and conflict-free memory management strategy, enabling seamless parallelism and reducing execution time while minimizing hardware resource consumption. Furthermore, the implementation incorporates several methods to effectively mitigate side-channel attacks, a common concern in hardware-based cryptosystem deployments. The proposed architecture is validated through implementation on an Artix-7 FPGA and Synopsys 14nm ASIC technology. Compared to state-of-the-art designs, our approach demonstrates superior performance while maintaining comparable hardware resource efficiency. Specifically, the hardware implementation on the Xilinx Artix-7 utilizes 12k LUTs, 6.9k FFs, 4 DSPs, and 9 BRAMs at clock frequency of 220 MHz.

Aissa SOULI

The objective of my work is the simulation and analysis of the protection of electrical networks against lightning strikes. To achieve this goal, I will use the simulation programs ATP/EMTP and MATLAB/SIMULINK to simulate a lightning strike in two cases: in the first case, simulate a lightning strike in an electrical networks without a surge arresters installed, and in the second case , simulating a lightning strike in an electrical networks with a surge arresters installed, to see the behavior of our electrical network in both cases, and to know the importance of surge arresters in the protection of electrical networks and also to validate and compare the results obtained by the two simulation programs.

Jiali Zhang, Wenhui Xu, Qi Zhou et al.

Dipole condensates, formed from particle-hole pairs, represent a unique class of charge-neutral quantum fluids that evade conventional vector gauge fields, making their electrodynamic responses difficult to probe in natural materials. Here, we propose a tunable platform using strongly interacting two-component ultracold atoms to realize dipole condensates and probe their coupling to rank-2 electric fields. By applying spin-dependent forces and treating spin as a synthetic dimension, we engineer a synthetic rank-2 electric field that induces measurable electrodynamic responses. We identify the atomic analog of perfect Coulomb drag: increasing intercomponent interactions leads to equal and opposite displacements of the centers of mass of the two spin components. Furthermore, a rank-2 electric field imprints a phase twist in the dipole condensate and generates a supercurrent of dipoles that obeys the dipolar Josephson relation -- a smoking gun for dipole condensation. Our results establish a powerful platform for exploring dipolar superfluidity under tensor gauge fields.

Ali Ehsan, Robin Preece

Joe W. Waters, Nathaniel J. Livesey, Michelle L. Santee et al.

We describe a novel scanning microwave limb sounder (SMLS) instrument that performs rapid and broad azimuth conical scans of Earth's limb while simultaneously scanning the limb in the vertical. This azimuthal scanning capability gives dramatic improvement in temporal and spatial coverage over that of previous limb sounding instruments. In a 1500-kilometer altitude, 52°-inclination Earth orbit, SMLS provides 6–8 vertical profile measurements separated by 1.9 hours every 24 hours everywhere between ±65° latitude, and 2–4 such measurements everywhere between ±(65–82°). Horizontal resolution is ∼50×50 km. Vertical resolution is ∼2 km for water vapor and cloud ice and ∼1–3 km for chemical species. In an equatorial orbit, emphasizing the tropics and subtropics, SMLS produces profile measurements every 1.9 hours everywhere between ±35° latitude. SMLS measurements address scientific issues of relevance to the upper troposphere, stratosphere, mesosphere, and lower thermosphere regions of the atmosphere (heights from ∼10 km to ∼100 km).

Li Qianwen

In recent years, people have been committed to studying how to recognize human behavior through the use of wearable devices and understand the intentions expressed by human actions, which has also attracted much attention in human-computer interaction. At present, research on dance mainly relies on computer simulation, while wearable devices can more realistically reflect the details and dynamic processes of dance movements. In order to realize the recognition of dancing human movements, this paper proposes a system that combines Motion capture technology and wearable devices, and uses wearable devices for recognition. Before the experiment began, we established a process for collecting and preprocessing dance action data. On the basis of in-depth research and analysis of Motion capture technology, we have successfully constructed a human Motion capture data-driven system, which can obtain the data needed by the human body to dance through wearable devices. After experimental verification, the system designed in this article performs excellently in recognizing human movements in dance. The recognition results not only contribute to dance training and correcting errors, but also gradually become an important way for dance learning, providing new ideas for dance learning and inheritance.

Bálint Hartmann, Tamás Soha, Michelle T. Cirunay et al.

Research on the vulnerability of electric networks with a complex network approach has produced significant results in the last decade, especially for transmission networks. These studies have shown that there are causal relations between certain structural properties of networks and their vulnerabilities, leading to an inherent weakness. The purpose of present work was twofold: to test the hypotheses already examined on evolving transmission networks and to gain a deeper understanding on the nature of these inherent weaknesses. For this, historical models of a medium-voltage distribution network supply area were reconstructed and analysed. Topological efficiency of the networks was calculated against node and edge removals of different proportions. We found that the tolerance of the evolving grid remained practically unchanged during the examined period, implying that the increase in size is dominantly caused by the connection of geographically and spatially constrained supply areas and not by an evolutionary process. We also show that probability density functions of centrality metrics, typically connected to vulnerability, show only minor variation during the early evolution of the examined distribution network, and in many cases resemble the properties of the modern days.

Roozbeh Torkzadeh, Jeroen van Waes, Vladimir Ćuk et al.

Kyung Min Kim, Jeong Suk Yang, Hyung Tae Kim et al.

Abstract Demand for increased scalability of oxide thin‐film transistors (TFTs) continues to rise, along with the need for ever‐higher integration densities and driving currents. However, the undesirable channel length (LCH)‐dependency renders short channels difficult. To overcome such behavior in back‐channel etched devices, back‐channel interface engineering using commercially favorable silicon oxide (SiOx) and the effects thereof on the electrical characteristics of fully integrated TFTs are investigated. Process‐dependent investigation reveals that a sequential formation of double‐layered SiOx with a defect control layer (DCL) effectively alleviates back‐channel damage. The proposed method imparts advanced functionality to conventional materials of SiOx. The DCL promotes oxygen inter‐diffusion to the oxygen‐deficient back‐channel, suppresses excess hydrogen inflow, and boosts out‐diffusion of residual copper from the back‐channel. This afforded excellent device uniformity and electrical characteristics with the proposed device, including field effect mobility of ≈14.0 ± 1.0 cm2 V−1 s−1, threshold voltage (Vth) of ≈1.22 ± 0.39 V, and subthreshold gate swing of ≈0.46 ± 0.09 V dec−1 at W/L = 4/7 µm. Furthermore, Vth variation when LCH decreased from 20 to 4 µm is dramatically suppressed from >11.39 V with the pristine device to 0.78 V with the proposed device, because of controlled back‐channel properties providing sufficient effective LCH.

Jingyu Park, Sungju Choi, Changwook Kim et al.

Abstract Oxide semiconductor transistors control the brightness and color of organic light‐emitting diode (OLED) displays in large‐screen televisions to portable telecommunications devices. Oxide semiconductor thin‐film transistors under driving conditions are required to maintain a steady current through the OLED for constant illuminance. Interestingly, for driving conditions under strong saturation where both gate and drain bias are high, a boosting phenomenon of the drain current is discovered, even with compensation of the threshold voltage. In this paper, the current boosting effect of self‐aligned InGaZnO transistors under driving conditions is comprehensively investigated. Based on experimental extraction methods, two distinct regions within the device are identified: an electron‐capture‐dominant region including electron trapping in the gate insulator and O–O dimer bond‐breaking, and an electron‐emission‐dominant region caused by peroxide formation. A dual‐transistor‐in‐series model is proposed, where each region is modeled as a local transistor. The current boosting phenomena as a function of time are well‐reproduced for various channel length devices, which validate the accuracy of the model. Better understanding of the underlying mechanisms enables increased effectiveness of compensation schemes for transistors under long‐term current‐driving conditions.

G. Regmi, Sangita Rijal, S. Velumani

Zinc oxide ultra-thin films doping with aluminum (AZO) were produced through radio frequency (rf) sputtering at a fixed pressure of 10 mTorr while varying the rf power between 80 and 140 W. The crystal structure of hexagonal Wurtzite was consistent throughout, with improved crystallinity observed at higher rf powers due to optimal diffusivity of the sputtered particles during nucleation and growth. The size of the crystallite was increased from 10.37 to 16.58 nm with increasing the rf power from 80 to 140 W. The Raman spectra provided evidence of the formation of ultra-thin AZO films, with discernable changes in morphology due to the influence of rf power. The value of optical band gap fluctuated between 3.49 and 3.58 eV as a function of rf power, a basis of the Burstein–Moss effect. The resistivity of the ultra-thin AZO films declined while augmenting rf power. A bilayer structure of intrinsic ZnO (i-ZnO) and AZO was fabricated and exhibited good transmittance, well-crystalline morphology, and excellent electrical conductivity. The optimized window layer (i-ZnO and AZO) was used to produce flexible Cu(In,Ga)Se2(CIGSe) solar cells with a photo conversion efficiency of 9.53%. Therefore, ultra-thin ZnO films exhibit potential as a favorable option for a window layer in the production of high-efficient flexible solar cells in cost effective way.